vt6655: Fix a possible sleep-in-atomic bug in vt6655_suspend

[ Upstream commit 42c8eb3f6e15367981b274cb79ee4657e2c6949d ]

The driver may sleep under a spinlock, and the function call path is:
vt6655_suspend (acquire the spinlock)
  pci_set_power_state
    __pci_start_power_transition (drivers/pci/pci.c)
      msleep --> may sleep

To fix it, pci_set_power_state is called without having a spinlock.

This bug is found by my static analysis tool and my code review.

Signed-off-by: Jia-Ju Bai <baijiaju1990@163.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>